Bypass protection for 4 LEDs up to 1000m
LEDs are fragile solid-state devices. An LED is essentially a diode, structured as a P-N junction that emits light when forward biased. One of the major causes of an electrical open in an LED is thermo-mechanical stress on the wire bonds. Other causes of LED open circuits are electrostatic discharge (ESD) events or surges induced by nearby lightning events. These threats are especially high in outdoor applications.
Open LED protection is designed as an electronic shunt which provides a current bypass in the case of an open circuit caused by a single LED failure. It is an internally triggered two-terminal device which automatically resets if the LED heals itself or is replaced. The protector is a voltage-triggered switch with low leakage on the order of microamps that becomes a low-impedance switch when it is triggered on, which minimizes power consumption. An LED in the on-state drops approximately 3.0V, which is not sufficient to turn on the protector device. Once an LED fails open, there is sufficient circuit voltage to trigger the protector to the on-state when it is placed in parallel with the LED.
PLED18 Series Devices Solution:
The PLED18 Series is designed to bypass 4 open LED in a string due to its minimum breakdown voltage of 18V.
The PLED18 Series can handle up to 1000mA of continuous current making them ideal for protecting 1W, 2W, and 3W LEDs<b< dd=""></b<>
If ESD is a concern, the IEC 61000-4-2 can be consulted to find information on the test method and transient waveform that should be used.